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GD32F20x User Manual
701
Figure 25-20. Read access timing diagram under async-wait signal assertion
Address
(EXMC_A[25:0])
Wait
(EXMC_NWAIT)
NRWTPOL = 0
Chip Enable
(EXMC_NEx)
Output Enable
(EXMC_NOE)
Data
(EXMC_D[15:0])
Address Setup Time
Data Setup Time
Memory Output
4 HCLK
Wait
(EXMC_NWAIT)
NRWTPOL = 1
Figure 25-21. Write access timing diagram under async-wait signal assertion
Address
(EXMC_A[25:0])
Wait
(EXMC_NWAIT)
NRWTPOL = 0
Chip Enable
(EXMC_NEx)
Write Enable
(EXMC_NWE)
Data
(EXMC_D[15:0])
Address Setup Time
Data Setup Time
3 HCLK
EXMC Output
1 HCLK
Wait
(EXMC_NWAIT)
NRWTPOL = 1
Synchronous access timing diagram
The relation between memory clock (EXMC_CLK) and system clock (HCLK) is as follows:
EXMC_CLK=
HCLK
CKDIV+1
CKDIV is the synchronous clock divider ratio, it is configured through the CKDIV control field
in the EXMC_SNTCFGx register.
1.
Data latency and NOR Flash latency
Data latency is the number of EXMC_CLK cycles to wait before sampling the data. The
relationship between data latency and NOR Flash specification’s latency parameter is as
follows:
For NOR Flash’s specification excluding the EXMC_NADV cycle, their relationship should be:
NOR Flash latency = DLAT + 2
For NOR Flash’s specification including the EXMC_NADV cycle, their relationship should be:
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
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Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...